Erik’s parents maintain that Karlsson is just a figment of his imagination. That might be but if so he is the best figment in the world. Karlsson lives on the roof and flies back and forth with the help of a helicopter rotor on his back. He considers himself the best Karlsson in the world! Erik’s parents maintain that Karlsson is just a figment of his imagination. That might be but if so he is the best figment in the world. Karlsson lives on the roof and flies back and forth with the help of a helicopter rotor on his back. He considers himself the best Karlsson in the world!